The term “nuclear protein” is a generic name of proteins functioning in cell nucleus. In nucleus there are genomic DNA serving as a plan of organism, and nuclear proteins are involved in replication, transcriptional regulation etc. of these genomic DNA. Typical nuclear proteins whose functions have been revealed include a transcription factor, a splicing factor, an intranuclear receptor, a cell cycle regulator and a tumor suppressor. These factors are closely related not only to life phenomena such as development and differentiation but also to diseases such as cancers (New Medical Science, “Tensha No Shikumi To Shikkan” (Mechanism of Transcription and Diseases) ed. by Masahiro Muramatsu). Accordingly, these nuclear proteins are expected as target proteins for developing low-molecular pharmaceutical preparations that regulate transcription and translation of specific genes, and it is desired to obtain as many nuclear proteins as possible.
The WW domain belongs to a new family of protein—protein interaction motifs resembling SH2, SH3, PH and PTB domains. It is known that this domain consists of about 40 amino acid residues containing 2 conserved tryptophan residues, and like the SH3 domain, binds to a proline-rich amino acid sequence (H. I. Chen and M. Sudol., Proc. Natl. Sci. 92, 7819–7823, 1995). As a result of X-ray crystallographic analysis of a WW domain/ligand conjugate, it was revealed that the three-dimensional structure of the WW domain is different from that of SH3 (M. J. Macias et al., Nature, 382, 646–649, 1996). Like other protein motifs, the WW domain is contained in the cytoskeleton system (P. Bork and M. Sudol TIBS, 19, 531–533, 1994), in proteins participating in the signal transduction system (H. I. Chen and M. Sudol., Proc. Natl. Sci., 92, 7819–7823, 1995), in a ubiquitin-protein ligase in the protein degradation system (O. Staub et al., EMBO J., 15, 2371–2380, 1996) and in a transcription activator (P. Bork and M. Sudol, TIBS, 19, 531–533, 1994), and is believed to play an important role in the intracellular signal transduction system.
The object of the present invention is to provide a novel protein present in human cell nucleus, a polynucleotide encoding this protein, and an antibody against this nuclear protein.